Kevin Smith is a bright guy who over the years has become a little too taken with his own persona, his own jokes, his own cult following — it's the filmmaker's equivalent of getting high on your own supply. No matter how awkwardly pontifical or ill-shapen his movies have gotten in the past 10 years — including his last, 2011's ploddingly self-righteous Red State — there's always a herd of noisy Jay and Silent Bob fanatics popping up to defend him as a genius. Smith seems to have bought the hype himself. In a guest column he wrote for the Hollywood Reporter last year, he actually referred to himself as a "naughty auteur." It's the sort of thing that would be hard for anyone other than, say, the eternally fabulous John Waters to get away with — and Waters would know better than to say it.

But even those of us who have grown weary of Kevin Smith might find a little sympathy for his latest picture, the body-horror tragicomedy Tusk, in which a madman yearns to re-create the bond he once had with a bulky, wrinkly, long-toothed marine mammal. Let me temper that recommendation: Tusk is kind of terrible, annoying and self-congratulatory in all the ways we've come to expect from Smith (without even, say, any of the silly sweetness of the 2008 Zack and Miri Make a Porno). But Tusk is at least trying to be about something. If you can squeeze past the movie's excess blubber, it's easy to see that even Smith — who maintains a large online fan base, thanks in part to SModcast, the podcast he does with longtime collaborator Scott Mosier — recognizes that the internet has opened up new channels for bad behavior and callousness. Tusk works hard, too hard, to be out-there: It wears its ambitions to become a midnight movie classic right there on its fat flipper. But there's something mournful beneath all its bluster. It's as if Smith were nursing a toothache of the soul, and this labored little movie was the best way he could figure to shake it off.

Tusk was inspired by a seemingly random news item that Smith first brought to light in a SModcast: A homeowner had posted a notice on a U.K. classifieds site offering free lodging to some lucky individual, with one catch: Said tenant would be required, now and then, to dress up as a walrus. Smith has taken this little squib and fleshed it out into a rambling tale of obsession and madness. It all begins so innocently: Los Angeles-based Wallace (Justin Long) and Teddy (Haley Joel Osment) host a popular podcast oh-so-cleverly called the Not-See Party, where, mostly, they just crack each other up with their constant patter of inside jokes. They're obsessed with a homemade video one of their listeners has sent in: While re-enacting a scene from one of the Kill Bill movies, a hapless Canadian kid lops his leg off with a sword.

Wallace heads out to Manitoba to interview this one-legged figure of pity — clearly, he's not above making fun of the kid. But his plans are derailed, and he finds himself without a story. Intrigued by a curious handwritten notice he spots in the men's room of a pub, he ends up trekking out to Middle of Nowhere, Manitoba, to meet eccentric, crusty, wheelchair-bound former seaman Howard Howe (Michael Parks, who played the Fred Phelps stand-in in Red State). At first Wallace is amused by Howe's Moby Dick-sized seafaring whoppers. Then, after imbibing too much spiked tea, he awakens to discover...

Those who wish to know nothing about the movie's central plot element should stop reading here. (And if you're the least bit squeamish, you should have some idea of the mild ewkiness you're in for, though Smith, to his credit, doesn't have much of a taste for torture gross-outs.) Howard, it turns out, was once lost at sea. Upon finding dry land, he also found his way into the welcoming embrace of a walrus, and, having been an abused child and all-around troubled dude, he'd never known such warmth and security. Arising from his whacked-out belief that walruses are superior to human beings, he has devoted his many lonely hours to designing a walrus "suit" in which to encase a human — in other words, Wallace. After his forced and grisly transformation, Wallace is a comically horrible sight, his eyes staring forlornly out of a shell of moist, putty-colored, pieced-together flesh, two horrible, whiskery tusks poking out right where his human mustache used to be.

Smith can't resist packing all kinds of shenanigans around this conceit, most of them involving the efforts of Teddy, Wallace's girlfriend Ally (Genesis Rodriguez), and a French-Canadian detective played by a bodaciously disguised Johnny Depp. The movie sags whenever it's supposed to be boisterously funny; Smith isn't deft enough to navigate the whipsaw tone changes of his own script. The best, creepiest moments involve the one-sided conversations between Howard and his weeping, sad-eyed captive. Parks makes a decent maniacal villain — he's elegant in a purely devious way, like a Masterpiece Theatre host gone off the deep end. But the movie really belongs to Justin Long, and only after he's encased in that terrible, blubbery suit. As the human Wallace, he wasn't as human as he thought: A good chunk of the meandering dialogue covers Ally's disappointment in his desire to make fun of everything — including one-legged kids — rather than to engage on a human level, as he used to do in the old days, before, perhaps, the internet bestowed its twisted version of fame upon him.

But as Walrus Wallace, he's a haunting blob of a movie centerpiece, an idea in search of a film worthy of him. Tusk isn't quite it. There's too much forced winking in it; everything is a goof, a lark, a Smith-style in-joke for the in-crowd. Still, at the end, it's unnerving to leave Wallace alone, forever, encased in that weird sarcophagus of flesh. He's a funny-ghastly vision, a waddling cautionary tale for those of us who fail to act like human beings while we have the honor of doing so.